We are switching most ChromeUtils.import calls to be treated as explicit variable declarations by ESLint. This has the advantage of triggering no-unused-vars more often (especially in jsm files), to find unused imports.

This doesn’t work where modules.json lists a file as exporting two symbols (only one of them might be used, so we haven’t weeded them out yet).

The better form declarations of const {Foo} = ChromeUtils.import(“resource://foo.jsm”, {}); are already handled according to the variables.

Performance

Florian landed some new about:performance UI pref’ed off, you can try it by flipping dom.performance.enable_scheduler_timing in about:config and then restart the browser before opening about:performance (warning: the browser will crash if you forget to restart). He also started investigating performance issues when reordering tabs.